Ebolavirus (EBOV) is a human epidemics associated with four sub-species, namely Bundibugyo virus (BDBV), Reston virus (RESTV), Sudan virus (SUDV) and TM Forest virus (TAFV). Among them, SUDV induces 50% fatality rate and longer progression to death. SUDV is a filamentous RNA virus that causes Ebola viral hemorrhagic fever (VHF), a severe and often fatal to human and non-human primates. Unfortunately, there is currently no effective drug or vaccine available against this type of virus. Thus, early diagnosis for such RNA virus is essential for its surveillance and control.
Many efforts have been made to develop fluorescence assays for nucleic acid detection. The general mechanism used in such approach lies in the absorption of the fluorophore-labeled probe single-stranded DNA (ss-DNA, also referenced as probe DNA; P-DNA) by nano-material to form a conjugate and accompanied by substantial fluorescence quenching. Following the specific hybridization with its target disease related DNA or RNA sequences, the formed double-stranded DNA (ds-DNA) or ds-DNA/RNA becomes more rigid and detaches from the surface of the nano-material with the recovery of fluorescence. Up to now, a handful of nano-materials including gold nanoparticles, single-walled carbon nanotubes and graphene have been successfully used in such assay, and most of these nano-materials are able to detect DNA or RNA at the nanomolar level.
Recently, a few of organic frameworks (MOFs) have been explored as fluorescence quenching platform for the detection of target DNA/RNA (e.g., Zhu, X. et al., Chem. Commun., 2013, 49, 1276; Chen, L. et al., Analyst., 2013, 138, 3490; Wang, G. Y. et al., J. Mater. Chem. A, 2014, 2, 2213; Wu, Y. et al., Nanoscale, 2015, 7, 1753; Tian, J. et al., Biosens. Bioelectron., 2015, 71, 1; Zhao, C. et al., J. Am. Chem. Soc., 2013, 135, 18786, Zhang, Z. X. et al., Angew. Chem. Int. Ed. 2014, 53, 4628; Yang, S. P. et al., Anal Chem., 2015, 87, 12206). Most studied MOFs are based on previously reported water stable nano-MOF, such as MIL-101 (Fang, J. M. et al., Analyst, 2014, 139, 801), MIL-88B (Tian, J. Q. et al., Biosens. Bioelectron., 2015, 71, 1), UiO-66 (Wu, Y. et al., Nanoscale, 2015, 7, 1753), UiO-66-NH2 (Zhang, H. T. et al., Chem. Commun., 2014, 50, 12069) and etc. However, such development is still at an infant stage and provided MOFs often suffer from a poor water stability and/or poor water stability significantly limiting their diagnostic use as a sensing platform.
Accordingly, there is a strong need for improved compounds which are easily obtainable in an economic way with sufficient water stability, water solubility and sufficient DNA or RNA binding ability which are suitable to form sensing platforms for target nucleic acid sequences such as in the diagnosis of viral infectious diseases and in particular Ebolavirus infections.